In order to gut fish, the abdominal cavity is initially opened by slitting the abdominal wall surrounding the abdominal cavity from the tail end along the abdominal seam while simultaneously separating the rectum within the region of the anus. The guts are subsequently removed by suction and progressively collected from the anus to the head. An apparatus for carrying out said method includes a conveyor with at least one fish receptacle for accommodating the fish to be processed while it lies on its back and for conveying said fish along a transport path with its tail pointing forward. A processing means is arranged above the transport path, which can be controlled relative to the transport path and parallel to the plane of symmetry of the fish. The processing means opens the abdominal cavity along the abdominal seam as well as removes the guts by suction. The apparatus further includes a means for acquiring specific fish data.
Such a gutting process is the object of German patent number DE 39 15 815. This document describes an apparatus in which the fish to be processed is transported while it lies on its back and its tail points forward, wherein the abdominal cavity is opened from the anus to the gill cavity along the abdominal seam and the guts are removed by suction.
German Democratic Republic patent number DD 45467 discloses a method for opening the abdominal cavity of live fish. The disadvantage of this method is that an additional circular knife is provided which engages the slot of a puncturing tool that penetrates the abdominal cavity of the fish from the gill cavity and emerges at an incision produced within the region of the anus after slitting the abdominal wall. The cutting accuracy which can be attained with this method is very low, i.e., the cuts frequently extend into the adjacent flesh because the colon opening cannot be exactly located and inferior qualities result. In addition, it is possible that the membranes above the blood kidney are damaged as a result of faulty cuts within the region of the colon, wherein contamination and consequently an inferior product quality result in this case.
According to the prior art cited in this document, a flawless result, i.e., a qualitatively satisfactory end product, cannot always be attained, even when utilizing a device with the previously described characteristics. However, this represents a decisive factor, in particular, with valuable fish. When processing these types of fish, the processing must occur with a high precision such that reliable results are attained. Flaws and imperfections such as colon and blood residues, damage to the wall of the abdominal cavity and the like which reduce the quality, need to be reliably prevented. This reliable processing also needs to be ensured when processing fish of different sizes.